Phosgene is a highly toxic gas which is colorless at room temperature. Phosgene sits in top 10% of the most toxic materials. It has also been known as a notorious chemical warfare agent (CWA) since it killed more than 100,000 people as a chemical weapon during World War I.
Once exposed on phosgene, the respiratory system is severely damaged, leading to the disease such as noncardiogenic pulmonary edema and emphysema and even death. Unlike other chemical warfare agents such as Sarin, Soman, Taburn, and DCP (diethyl chlorophosphate), phosgene has a latent period with no apparent symptoms, during which pulmonary edema is developed due to its unique toxicity that leads to death.
There is no method to detect patients exposed on phosgene at the latent stage or to determine the possibility of the development of pulmonary edema thereby. The production of Sarin, Soman, and Taburn is limited by law but phosgene is widely used in industry and used as a starting material for the production of other compounds, insecticides, pharmaceuticals and isocyanate-based polymers. Therefore, there is a relatively high chance of a disaster occurring due to the exposure by an accident or other routes.
So, human lives can be damaged or lost by intentionally induced exposure on phosgene through war or terror or massive civil damage can be induced by the exposure through an industrial accident, making phosgene a highly dangerous material.
Therefore, it is very important to detect phosgene fast and accurately for protecting human lives. It is also necessary to develop a method to detect phosgene selectively from other gases or CWAs.
Sensors are under development to detect CWA by detecting the changes of fluorescence or color development (Santu Sarkar and Raja Shunmugam. Chem. Commun., 2014, 50, 8511-8513). It is still requested to develop a fluorescent chemical sensor or color sensor to detect CWA faster and more sensitively within a few seconds. Moreover, a sensor to detect a target material from other CWAs or gases has not been developed yet.
Thus, the present inventors have developED a method to detect phosgene selectively fast and accurately within a few seconds by detecting the changes of fluorescence or color development. In the course of the study, the present inventors confirmed that the compound of the present invention can detect phosgene and DCP (diethyl chlorophosphate) fast and accurately within a few seconds at even nM unit by screening the changes of fluorescence and color development and can detect phosgene and DCP selectively from other CWAs or gases, leading to the completion of the present invention.